#include <iostream>
#include <queue>
using std::cout;using std::endl;
int main(){
        std::queue<int> s;
        s.push(1);
        cout<<"1 进入队列"<<endl;
        s.push(2);
        cout<<"2 进入队列"<<endl;
        s.push(3);
        cout<<"3 进入队列"<<endl;
        cout<<"队列的大小:"<<s.size()<<endl;
        cout<<"队列首元素:"<<s.front()<<endl;
        cout<<"开始移出队首元素"<<endl;
        while(!s.empty()){
        std::cout<<s.front()<<" ";//打印队首元素
        s.pop();//删除队首元素
    }
        s.empty()?cout<<"\n队列为空":cout<<"\n队列非空";
        return 0;
}
